Ice cream machine including a controlled input to the freezing chamber

ABSTRACT

An ice cream machine for cooling liquid ice cream into frozen ice cream includes an evaporator system with a secondary evaporator. The evaporator system includes a cooling chamber having an ice cream input and an ice cream output. A valve can be placed at the ice cream input to achieve dry freeze operation. The valve can prevent the cooling chamber from being completely filled.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

The present application is related to U.S. patent application Ser. No.09/639,062 filed Aug. 15, 2000 entitled, “Batch Process and ApparatusOptimized to Efficiently and Evenly Freeze Ice Cream”, which is acontinuation-in-part of U.S. patent application Ser. No. 09/234,970,filed by Ross on Jan. 21, 1999, now U.S. Pat. No. 6,119,472, which is acontinuation-in-part of U.S. patent application Ser. No. 09/083,340,filed by Ross on May 22, 1998, now U.S. Pat. No. 6,101,834, which is acontinuation-in-part of U.S. patent application Ser. No. 08/869,040,filed Jun. 4, 1997, now U.S. Pat. No. 5,755,106, which was acontinuation of U.S. patent application Ser. No. 08/602,302, filed Feb.16, 1996, abandoned. The above-referenced U.S. patent application Ser.No. 09/639,062, U.S. Pat. No. 6,101,834, U.S. Pat. No. 6,119,472, andU.S. Pat. No. 5,755,106 are incorporated herein by reference.

The present application is also related to U.S. application Ser. No.10/074,268, entitled “Ice Cream Machine Including a Secondary CoolingLoop” assigned to the assignee of the present application, filed on aneven date herewith by Ross et al.

FIELD OF THE INVENTION

The present invention generally relates to refrigeration or coolingsystems. More particularly, the present invention relates to anevaporator design for refrigeration or cooling systems or to a mode ofoperation for an ice cream machine.

BACKGROUND OF THE INVENTION

Ice cream or frozen custard machines, as well as other systems forcooling or freezing food stuffs, condiments, or other materials,typically include an evaporator situated proximate the material beingchilled. For example, in ice cream machines and soft serve machines,liquid ice cream (e.g., the mix) is typically inserted in a freezingchamber or barrel associated with the evaporator and is removed from thebarrel as solid or semi-solid ice cream. The evaporator removes heatfrom the freezing chamber as a liquid refrigerant, such as, FREON®,ammonia, R-404a, HP62, or other liquid having a low boiling point,changes to vapor in response to the heat from the liquid ice cream.Typically, the evaporator is partially filled with vapor as the liquidrefrigerant boils (e.g., becomes vapor) in the evaporator.

Quick freezing of liquid ice cream and high capacity are desirousfeatures of ice cream makers. In addition, custard or ice cream qualityand efficient manufacture of such custard or ice cream are dependentupon maintaining a constant evaporator temperature (e.g., constantbarrel temperature). The barrel temperature must be kept in a properrange for making ice cream. If the custard or ice cream is allowed tobecome too cold, the mix or liquid ice cream in the evaporator becomeshighly viscous and can block the travel of the ice cream through thebarrel. Blockage of the barrel in the freezing process is commonly knownas “freeze up”. If the ice cream or custard is allowed to become warm,its texture is adversely affected.

Maintaining the temperature of the barrel at a constant level isparticularly difficult as ice cream flow rates through the machine varyand change the cooling load on the evaporator. For example, more heatdissipation is required as more ice cream is produced (i.e., the flowrate is increased). Additionally, if the barrel temperature is too low,refrigerant flood-back problems can adversely affect the operation ofthe compressor. For example, if the refrigerant is not fully evaporatedas it reaches the compressor, the liquid refrigerant can damage thecompressor.

Problems associated with temperature consistency are exacerbated duringperiods of non-production (e.g., an idle mode, a period of slow sales, ahold mode, etc.). Generally, ice cream machines, particularly soft servemachines,.can experience non-production modes, periods of little or lowproduction operation or a “hold” mode. During this mode, liquid icecream and frozen ice cream product remain in the barrel (the coolingchamber) awaiting to be processed. However, due to the low demand forice cream, ice cream is not removed from the barrel. The ice cream inthe barrel can be subjected to temperature fluctuations during theseperiods of non-production due to heat infiltration.

Heretofore, ice cream machines have required that the refrigerationsystem (the compressor) be cycled on and off to maintain the ice creamin the barrel at the appropriate temperature. Such conventional systemshave been unable to accurately maintain the barrel temperature at aproper and consistent temperature. For example, the fairly largecompressors associated with the ice cream machine cool (e.g., overcool)the barrel down and then allow it to warm back up before the compressoris engaged to cool the barrel. The temperature within the barrelfluctuates according to a sawtooth wave. The gradual freezing andthawing causes the product to break down such that texture of theproduct becomes more grainy and less desirable to the taste.

Further, conventional systems have allowed the liquid ice cream mix tohave constant access to the barrel. Generally, conventional systems haveincluded a liquid ice cream reservoir connected to the evaporator via anaperture. The allowance of liquid ice cream to enter the barrel duringnon-production times contributes to the warming of the ice cream in thebarrel, thereby affecting the quality of the ice cream within the barrelwhen liquid ice cream is allowed to fill the barrel, the liquid icecream can become frozen against the barrel, thereby reducing thefreezing efficiency of the barrel.

Further, conventional systems have allowed the ice cream product to beperiodically and automatically mixed (i.e., beaten) in the evaporatorduring non-production modes or slow sales periods. Overbeating of theice cream product results in poor ice cream texture and less desirabletaste.

Thus, there is a need for an ice cream machine which can operate in ahold mode and not allow the barrel temperature to fluctuate drastically.Further still, there is a need for a process and a machine which canmore efficiently and more evenly cool ice cream. Even further still,there is a need for a frozen machine which utilizes a barrel andmaintains the ice cream product at a consistent temperature.

Yet even further still, there is a need for a process or method whichdoes not allow liquid ice cream to affect the temperature in the barrelwhile in a hold or non-production mode. Yet even further, there is aneed for an ice cream machine which does not allow the chamber wall tobecome coated with ice cream. Further still, there is a need for anevaporator and a control system for an ice cream machine which preventsbreakdown of the ice cream product during slow sales periods. Further,there is a need for a hold mode for an ice cream machine which requireslittle or no bearing of the ice cream product.

SUMMARY OF THE INVENTION

An exemplary embodiment relates to an ice cream making system. The icecream making system includes an evaporator including a cooling chamberand at least one valve. The cooling chamber has an ice cream input andan ice cream output. The at least one valve is provided at the ice creaminput and is capable of preventing ice cream from entering the coolingchamber.

Yet another embodiment relates to an evaporator for an ice cream makingsystem. The evaporator includes an interior surface defining a coolingchamber for chilling a product, an evaporator chamber and a valve. Thecooling chamber has an ice cream input and an ice cream output. Theevaporator chamber surrounds the cooling chamber. The valve is in serieswith the ice cream input.

Yet another embodiment relates to a method of manufacturing ice cream.The method utilizes an ice cream machine having a cooling chamber. Themethod includes providing liquid ice cream contents into the coolingchamber through a valve. The valve prevents the cooling chamber frombeing more than 75% filled during a hold mode. The method also includescooling the ice cream contents in the cooling chamber and removingfrozen ice cream from the cooling chamber. Still another embodimentrelates to ice cream machine including an evaporator having a coolingchamber. The cooling chamber has an ice cream input and an ice creamoutput. The ice cream machine also includes means for restricting accessthrough the ice cream input to the cooling chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will hereafter be described with reference to theaccompanying drawings, wherein like reference numerals denote likeelements, and:

FIG. 1 is a schematic diagram illustrating an advantageous ice creammaking system according to an exemplary embodiment;

FIG. 2 is a schematic diagram illustrating another advantageous icecream making system according to another exemplary embodiment;

FIG. 3 is a state diagram showing the operation of the systemsillustrated in FIGS. 1 and 2;

FIG. 4 is a more detailed side cross-sectional view of an evaporator foruse in the systems illustrated in FIGS. 1 and 2;

FIG. 5 is a more detailed side planar view of an alternative evaporatorfor use in the systems illustrated in FIGS. 1 and 2;

FIG. 6 is a more detailed side planar view of an alternative evaporatorfor use in the systems illustrated in FIGS. 1 and 2;

FIG. 7 is more detailed side planar view of an alternative evaporatorfor use in the systems illustrated in FIGS. 1 and 2;

FIG. 8 is a general block diagram of a gate, valve and auger controlsystem for the ice cream machine systems illustrated in FIGS. 1 and 2;and

FIG. 9 is a flow diagram showing exemplary operation of the systemsillustrated in FIGS. 1 and 2.

DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENT OF THEPRESENT INVENTION

A soft serve, frozen custard, or ice cream machine or making system 10is diagrammatically shown in FIG. 1. Ice cream machine 10 includes acooling or refrigeration system 12 and an evaporator 20. Refrigerationsystem 12 can include any number of components for providing andprocessing liquid refrigerant to and receiving and processing a vaporrefrigerant from evaporator 20. For example only, system 12 can includean expansion device, such as, a valve, a shut-off device, such as, asolenoid valve, a sight glass, a filter, a condenser, a compressor, anaccumulator, and a valve. Although not limited to such systems, system12 can utilize any of the components or systems described in U.S. Pat.Nos. 6,119,472, 6,101,834, 5,755,106, and application Ser. No.09/639,062.

Evaporator 20 can be a system including a number of components on asingle integral unit. For example only, evaporator 20 can include acylindrical cooling tank, a secondary evaporator, and an auxiliary tank.Evaporator 20 can have a design similar to any of the evaporatorsdiscussed in U.S. Pat. Nos. 6,119,472, 6,101,834, 5,755,106, andapplication Ser. No. 09/639,062. Evaporator 20 is modified to include asecondary evaporation or another jacket for maintaining the temperaturewithin evaporator 20 during non-production modes.

Evaporator 20 includes a first refrigerant input 40, a first refrigerantoutput 42, a liquid ice cream input 44, and an ice cream output 46.Evaporator 20 further includes a second refrigerant input 41 and asecond refrigerant output 43. Refrigeration system 12 utilizesrefrigerant input 40 and refrigerant output 42 to provide primarycooling for ice cream making system 10. Refrigerant input 40 and output42 are in fluid communication with an evaporator chamber which surroundsa cooling chamber between ice cream input 44 and ice cream output 46.Output 42 can also be coupled to an auxiliary evaporator tank asdescribed below with reference to FIG. 4.

With reference to FIG. 3, system 10 can manufacture ice cream or otherfrozen or semi-frozen food stuff in an operational mode 61. Ice creamcan be manufactured utilizing a quick draw gate which creates ice creamwhenever gate 52 is opened. During the manufacture of ice cream in mode61, system 10 uses the primary cooling loop associated with input 40 andoutput 42. Alternatively, both the primary evaporator chamber and thesecondary evaporator chamber (the secondary loop associated with input41 and output 43) can be utilized.

When demand ceases, system 10 operates in a non-production mode 62. Whendemand returns, such as, when gate 52 is opened, system 10 returns tomode 61. Various sub-states or intervening states may occur betweenmodes 61 and 62. For example, system 10 maynot reach a non-productionmode until the temperature within evaporator 20 reaches a particularlevel. Further, system 10 may be maintained in mode 61 until ice creamis not demanded for a period of time or until the temperature withinevaporator 20 falls below a predetermined level after gate 52 is closed.

Advantageously, when system 10 operates in a non-production mode 62, itmaintains the contents within evaporator 20 at a consistent temperature.Non-production mode 62, such as, an idle mode, or hold mode, refers toany period of time at which system 10 is not allowing ice cream to exitoutputs 46 and yet ice cream product, whether or not completed orpartially completed, remains in the freezing chamber of evaporator 20.The non-production mode can be utilized during periods of slow sales,when system 10 is idling between business hours (system 10 is idle forthe night), etc.

In mode 62, refrigeration system 12 (FIG. 1), second refrigerant input41 and second refrigerant output 43 maintain the interior coolingchamber of evaporator 20 at a consistent temperature. A secondaryevaporator chamber is in fluid communication with input 41 and output43. The secondary evaporator can encompass the primary evaporatorchamber associated with input 40 and output 42.

The secondary evaporator preferably cools refrigerant trapped within theprimary evaporator chamber, thereby acting as a second loop for coolingthe primary refrigeration loop (the primary evaporator chamber). Thetrapped refrigerant within the primary evaporator surrounding theinterior freezing chamber provides a stabilizing effect to hold andtransfer temperature into the ice cream product held within the interiorcooling chamber.

The refrigeration system 12 can utilize a primary compressor systemand/or a secondary compressor system to provide refrigerant to thesecondary evaporator. The secondary evaporator can be any or anycombination of wrapped tubing, refrigeration jackets, and/or chambers.By maintaining the temperature at a more consistent temperature viarefrigerant input 41 and refrigerant output 43, fluctuations in producttemperature that can break down the ice cream and cause poor tasting icecream are reduced. Further, product which has been left in the interiorchamber for prolonged period of time is not wasted.

In one embodiment in which system 10 is configured as a soft serve icecream machine, ice cream can be stored in the interior chamber withinthe barrel to keep it at the appropriate temperature between draws(e.g., servings). This advantageously allows ice cream to be serveddirectly from evaporator 20 and eliminates the need for a dippingcabinet or other refrigeration unit for storing post manufactured icecream. In this way, ice cream directly from the machine can beimmediately served.

Applicant has found that by using a secondary cooling loop (e.g.,secondary evaporator between input 41 and output 43), a consistenttemperature can be provided in the interior chamber for long periods oftime, such as, 60 hours. Accordingly, over long periods of time innon-production mode 62, the contents of the interior chamber do not needto be emptied and discarded due to on/off cycling. Rather, the contentscan remain in evaporator 20 and be served accordingly. Further, sinceice cream is not discarded, the interior chamber does not need to becleaned after each entry into non-production mode 62.

According to one embodiment, at least one non-positive shutting controlvalve can be provided at input 40 to the primary evaporator. Liquidrefrigerant is allowed to enter through the control valve to evaporator20 (to the first cooling loop of evaporator 20). Allowing liquidrefrigerant through input 40 in a metered but continuous fashion allowsthe liquid in the first stage loop to become saturated and subcooled.The liquid refrigerant completely fills the first stage loop and itspresence acts as a stabilizing effect on temperature swings by means ofthermal mass and thermal transfer.

According to another preferred embodiment, machine 10 can control auger56 at different speeds during different periods of production. Duringproduction of ice cream (mode 61), machine 10 allows auger 56 to spin ata first speed (slow rpm) for production. When gate 52 is open, auger 56spins at a second speed (a faster rpm) for discharging product throughoutput 46. Various speeds can be chosen in accordance with designcriteria to achieve highest production and optimal discharge rates.

System 10 further includes an advantageous ice cream transport controlsystem. Ice cream is provided at ice cream output when a gate 52 isopened. Gate 52 is preferably linked to a valve 54 at ice cream input44. Accordingly, when gate 52 is opened and closed, valve 54 is alsoopen and closed. A delay for opening and closing valve 54 after gate 52is opened can also be implemented by a control mechanism. In oneembodiment, once opened, valve 54 can remain open until a particularcapacity is reached in the cooling chamber.

Valve 54 can be controlled by mechanical linkage coupled to gate 52.Alternatively, an electronic control system can be utilized to controlthe opening of valve 54 with respect to gate 52.

Liquid ice cream is not allowed to enter the interior chamber and warmthe contents of interior chamber when gate 52 is closed and system 10 isin a hold or non-production mode 62 (FIG. 3). In this way, valve 54 onlyallows an appropriate amount of mix to be in the interior chamberaccording to dry barrel technology. Further still, applicants have foundthat by limiting the quantity of material within the interior chamber,system 10 operating as a direct draw machine produces higher qualityfresh ice cream having a superior taste. Product is produced with lowoverrun, thereby operating with results similar to a standard machine.

In another preferred embodiment, machine 10 utilizes valve 54 to meterand limit the amount of product stored in evaporator 20. By eliminatingthe amount of products stored in evaporator 20, the surface areaavailable for production of product is increased, thereby increasing thespeed at which ice cream is frozen. Faster freezing generally results ina better ice cream product texture.

As discussed above, since the amount of custard stored in the barrel ofevaporator 20 is minimized (the heat exchange area is maximized), a moreeffective surface area for production is achieved. This is a significantadvantage over conventional soft serve ice cream machines in whichliquid ice cream product fills evaporator 20 (e.g., the freezing chamberis flooded). With such conventional systems, the inner wall of thechamber is coated with frozen product and becomes less effective forfreezing the remaining product in the chamber for new product.

According to another embodiment, the dry barrel technology discussedabove can be implemented via valve 54. Valve 54 can be a metering valvecontrolled by an actuator. An electric control circuit coupled to asensor can ensure that actuator restricts the chamber to be less thanhalf-filled during non-production modes. Preferably, the freezingchamber in evaporator 20 is 25% to 50% filled with pre-made product. Aconventional machine typically allows of the chamber to be 75 to 100%filled with pre-made product. The metering valve is controlled to bepositively shut when gate 52 is shut and ice cream is not drawn fromevaporator 20. This allows the barrel to store pre-made product but onlyhave 25-50% of the barrel full of pre-made product, thereby resulting infaster freezing of new product.

In addition, a control circuit or system is preferably provided whichprevents an auger 56 within the interior chamber from overbeating thecontents of interior chamber when gate 52 is closed. Embodiments ofcontrol systems mechanisms and schemes for system 10 are described withreference to FIG. 8. The control schemes monitor the operation of auger56 and valve 54.

With reference to FIG. 2, an ice cream making system 100 issubstantially similar to ice cream making system 10. However,refrigeration system 12 of FIG. 1 includes a primary refrigerationsystem 112 and a secondary refrigeration 114. Systems 112 and 114 canshare components. Preferably, systems 112 and 114 have separatecompressors. Alternatively, system 100 can include three or morerefrigeration systems if three or more evaporator chambers or coils areutilized by evaporator 20.

Although evaporator 20 is shown as having four separate interfaces(inputs 40 and 41 and outputs 42 and 43) in FIGS. 1 and 2, theinterfaces can be integrated together and/or separately divided withinevaporator 20. For example, a gate or valve can be used to divertrefrigerant from a single supply line to input 40 and input 41 locatedwithin evaporator 20. Similar systems can be designed for outputs 42 and43.

Primary refrigeration system 112 preferably includes a relatively largecompressor for use in making ice cream during normal operatingtemperatures. A smaller compressor can be utilized in secondaryrefrigeration system 114. The smaller compressor can more efficientlyprovide limited amounts of refrigerant to evaporator 20. Preferably, thesecondary compressor is rated between ¼ and ¾ horsepower, depending ondesign. In a preferred embodiment, a ⅓ horsepower rating is utilized.The primary refrigeration system 112 can utilize a compressor with a 1½to 3 horsepower or more rating. In a preferred embodiment, a compressorrated at a ½ horsepower rating is utilized. The use of the smallercompressor during mode 62 (FIG. 3) reduces energy consumption. Limitersmay be used to make the capacity of a 1½ to 3 HP compressor act likesmaller unit.

In an alternative embodiment, a separate condenser unit can also beprovided for the secondary evaporation chamber and the hopper.

With reference to FIGS. 4-7, more detailed drawings of alternativeembodiments of evaporator 20 (FIGS. 1 and 2) are shown. Each of theembodiments provides for an evaporator with a primary evaporator chamberand a secondary evaporator chamber. The secondary evaporator chamber isused to advantageously maintain the interior chamber at an appropriatecooling temperature. In FIGS. 4-7, reference numerals having the samelast two digits are substantially similar unless otherwise noted.

With reference to FIG. 4, an evaporator 124 includes an auxiliaryevaporator tank 126, a primary evaporator chamber 128, and a secondaryevaporator 130. Primary evaporator chamber 128 is provided about aninterior cooling chamber 134 which can include an auger such as auger 56(FIG. 1). Chamber 134 can be defined by a 0.125 inch thick stainlesssteel tube 135 having exemplary dimensions of a 4 inch outer diameter.Chamber 128 can be defined by a stainless steel tube 129 havingexemplary dimensions of an inner diameter of 4.5 inches and a length of18 inches−20.5 long.

Chamber 134 includes a liquid ice cream input 142 which can becontrolled by a valve and an ice cream output 144 which can becontrolled by a gate. Preferably, chamber 134 has a volume ofapproximately 226 cubic inches.

Evaporator chamber 128 includes a refrigerant input 152 corresponding torefrigerant input 40 and a refrigerant output 154 corresponding torefrigerant output 42 (FIGS. 1 and 2). Preferably, evaporator chamber128 has a volume of approximately 60 cubic inches (e.g., length of 18inches and a jacket width of 0.25 inches).

Auxiliary tank 126 includes a refrigerant output 156 which can becoupled to refrigeration system 12. Tank 126 operates as an accumulatorsimilar to the accumulator described in U.S. Pat. Nos. 6,119,472 and5,755,106. Tank 126 should not be confused with secondary evaporator 130which operates in parallel with evaporator chamber 128, rather than inseries with chamber 128 as tank 126. operates. Secondary evaporator 130includes a refrigerant input 158 corresponding to refrigerant input 41(FIGS. 1 and 2) and a refrigerant output 160 corresponding torefrigerant output 43. Preferably, secondary evaporator 130 is comprisedof copper tubing wrapped completely around the barrel associated withevaporator chamber 128.

The tubing associated with secondary evaporator 130 can be ⅜ coppertubing. The tubing is closely wrapped in a single layer from end-to-endof evaporator chamber 128. Alternatively, other wrapping configurationsand tubing materials and sizes can be utilized. Evaporator 130 caninclude two or more layers of tubing.

With reference to FIG. 5, an evaporator 224 is substantially similar toevaporator 124 including a refrigerant input 252 and a refrigerantoutput 254. Output 254 can be coupled to system 12 (FIG. 1) or system112 (FIG. 2). Evaporator 224 does not include an auxiliary evaporatortank such as evaporator tank 126 in FIG. 4.

With reference to FIG. 6, evaporator 324 includes a secondary evaporator350. Secondary evaporator 350 is defined by an outer barrel 355, and aninner barrel 360. A primary evaporator chamber 328 is defined by anintermediate barrel 360 and an inner barrel 365. Secondary evaporator350 includes a refrigerant input 370 and a refrigerant output 380.Evaporator 324 can also include an auxiliary evaporator tank such astank 126 (FIG. 4). Inner barrel 365 defines interior cooling chamber334. In a preferred embodiment, inner barrel 365 has an outer diameterof 4 inches and a length of 18 inches. Barrel 360 has an outer diameterof 4.76 inches and a length of 18 inches, and barrel 355 has an outerdiameter of 5.25 inches and a length of 18 inches. Barrels 355, 360, and365 can be 0.125 inches thick and manufactured from stainless steel.

With reference to FIG. 7, evaporator 424 includes secondary evaporator452 including a double wrap of copper tubes. A first wrap 480 isprovided about a second wrap 482. Second wrap 482 is provided aboutevaporator chamber 450. Chamber 450 includes a refrigerant input and arefrigerant to output similar to refrigerant input 352 and 354 (FIG. 6).Wraps 480 and 482 are provided from end-to-end of chamber 450.

Second wrap 482 includes a refrigerant input 490 and a refrigerantoutput 492. First wrap 480 includes a refrigerant input 494 and arefrigerant output 496. Refrigerant input 490 and refrigerant output 492can be coupled to a separate refrigeration system than that used forwrap 480 and chamber 450. Similarly, refrigerant input 494 and output496 can be utilized with a different compressor or refrigeration systemthan that used for wrap 482 and chamber 450. Preferably, wraps 480 and482 are provided on top of each other.

With reference to FIG. 8, a control system 500 is provided to moreaccurately control the temperature and consistency of product withininterior chamber 134 during non-production mode 62. For example, controlsystem 500 can include electronics or mechanical devices to ensure thatvalve 54 is open and closed simultaneously with gate 52. Alternatively,a delay can be utilized between opening and closing gate 52 with respectto valve 54.

Auger 56 is controlled by control system 500 to ensure auger 56 stopswhen the interior cooling chamber within evaporator 20 reaches anappropriate temperature. By sensing the amperage being provided throughthe motor associated with auger 56, the consistency of the contentswithin interior chamber 134 can be determined. The consistency canrepresent the appropriate temperature associated with the contents inevaporator 20. When the amperage is at the appropriate level, controlsystem 500 can turn off the motor which drives auger 56, therebypreventing overbeating of the contents in evaporator 20.

Once gate 52 is opened, the motor can be reset and allowed to run untilgate 52 is closed. After gate 52 is closed, the motor will continue torun until current sensed through the motor indicates that theappropriate temperature in interior chamber 134 is reached.Alternatively, control schemes can be utilized to stop auger 56appropriately. For example, system 500 can utilize a temperature sensorsituated in chamber 502 or chamber 134. Preferably, control system 500includes a micro switch or other device for sensing when gate 46 isopened to re-engage the motor which drives auger 56.

With reference to FIG. 9, the various modes associated with systems 10and 100 described with references to FIGS. 1 and 2 are discussed. In afirst mode, or production mode 602, manufacture of an ice cream productcan begin. Generally, the production mode operates auger 56 and uses aprimary evaporator associated with refrigeration input 40 andrefrigeration output 42. An operator can open gate 46 and remove icecream from evaporator 20 in an operational mode 604. When gate 52 isopen, valve 54 is open, thereby allowing liquid ice cream intoevaporator 20. After gate 46 is closed and valve 44 is closed, system 10can enter a non-production mode 606.

Non-production mode 606 can occur once the temperature within evaporator20 reaches a particular temperature. In mode 606, the primary evaporatorand auger are utilized. Similarly, as ice cream is removed, the augerand primary evaporator are utilized. In mode 606, the secondaryevaporator is utilized and the auger is stopped to prevent overbeatingof the ice cream.

The term “coupled”, as used in the present application, does notnecessarily mean directly attached or connected. Rather, the term“coupled” in the present application means in fluid or electricalcommunication there with. Two components may be coupled together throughintermediate devices. For example, the evaporator input is coupled tothe condenser output even though the expansion valve, accumulator/heatexchanger, and sight glass are situated between the evaporator input andthe condenser output.

It is understood that, while the detailed drawings and specific examplesgiven to describe the preferred exemplary embodiment of the presentinvention, they are for the purpose of illustration only. The apparatusof the invention is not limited to the precise details and conditionsdisclosed. For example, although food stuffs and ice cream arementioned, the invention may be utilized in a variety of refrigerationor cooling systems. Further, single lines for carrying liquidrefrigerant can represent multiple tubes. Additionally, although aparticular valve, accumulator, compressor, condenser, and filterconfiguration is shown, the advantageous machine can be arranged inother configurations. Further still, the evaporator barrel and freezercan have any number of shapes, volumes, or sizes. Various changes can bemade to the details disclosed without departing from the spirit of theinvention, which is defined by the following claims.

What is claimed is:
 1. An ice cream making system, comprising: anevaporator including a cooling chamber, the cooling chamber having anice cream input and an ice cream output, wherein liquid ice cream isprovided at the ice cream input and frozen ice cream is provided at theice cream output; a gate at the ice cream output; at least one valve atthe ice cream input, the valve allowing the liquid ice cream to enterthe cooling chamber and the valve preventing the liquid ice cream fromentering the cooling chamber in response to a control input; and acontrol system coupled to the control input, the control system ensuringthat the valve is closed when the gate is closed, wherein the valve iscontrolled to ensure that the cooling chamber is no more than 75 percentfilled during a hold mode, the hold mode being a state whereinadditional ice cream is not being provided to the cooling chamber. 2.The ice cream making system of claim 1, wherein the control systemcontrols the valve to prevent the cooling chamber from being more than50 percent filled.
 3. The ice cream making system of claim 2, whereinthe valve is controlled to maintain the cooling chamber filled to 25-50percent.
 4. The ice cream making system of claim 1, wherein the valveand the gate are operably linked to open and close in coordination. 5.The ice cream making system of claim 1, wherein the gate and the valveare controlled so that the valve is opened when the gate is opened. 6.The ice cream making system of claim 5, wherein the valve is maintainedopened after the gate is opened until an appropriate level of the liquidice cream enters the cooling chamber.
 7. The ice cream king system ofclaim 1, wherein the evaporator includes a primary evaporator chamberand a secondary evaporator chamber, the primary evaporator chamber beingprovided about the cooling chamber and the secondary evaporator chamberbeing provided about the primary evaporator chamber.
 8. The ice creammaking system of claim 1, wherein the evaporator further includes aprimary evaporator chamber about the cooling chamber and a copper tubeprovided about the primary evaporator chamber, the copper tube having afirst end associated with a second refrigerant input and a second endassociated with a second refrigerant output.
 9. An evaporator for an icecream making system, the evaporator comprising: an interior surfacedefining a cooling chamber for chilling a product, the cooling chamberhaving an ice cream input and an ice cream output; an evaporator chambersurrounding the cooling chamber; a valve in series with the ice creaminput, the valve being controlled to ensure that the cooling chamber is50 percent or less filled; a secondary evaporator about the secondcylinder, wherein the secondary evaporator is a copper tube; and anauxiliary evaporator for collecting vapor refrigerant exiting theevaporator chamber.
 10. The evaporator of claim 7, wherein the valve iscontrolled to ensure that the cooling chamber is less than 50 percentfilled.
 11. The evaporator of claim 10, wherein the cooling chamber isdefined by a first cylinder and the primary evaporator chamber isdefined by a space between the first cylinder and a second cylinder, thesecond cylinder being about the first cylinder.
 12. The evaporator ofclaim 9, wherein the valve is a metering valve.
 13. The evaporator ofclaim 9, further comprising an auxiliary evaporator tank coupled to theevaporator chamber.
 14. An evaporator for an ice cream making system,the evaporator comprising: an interior surface defining a coolingchamber for chilling a product the cooling chamber having an ice creaminput and an ice cream output; an evaporator chamber surrounding thecooling chamber; a valve in series with the ice cream input the valvebeing controlled to ensure that the cooling chamber is 50 percent orless filled; and an auxiliary evaporator for collecting vaporrefrigerant exiting the evaporator chamber wherein the cooling chamberis defined by a first cylinder and the evaporator chamber is defined bya space between the first cylinder and a second cylinder the secondcylinder being about the first cylinder, a secondary evaporator aboutthe second cylinder, wherein the secondary evaporator is a chamberdefined by the second cylinder and a third cylinder, the third cylinderbeing about the second cylinder.
 15. The evaporator of claim 4, whereinthe valve is controlled to ensure that the cooling chamber is 50 percentor less filled.
 16. A method of manufacturing ice cream, the methodutilizing an ice cream machine having a cooling chamber, the methodcomprising: providing liquid ice cream contents into the cooling chamberthrough a valve, the valve preventing the cooling chamber from beingmore than 75 percent filled during a hold mode, the hold mode being astate where additional ice cream is not produced; cooling the liquid icecream contents in the cooling chamber; and removing frozen ice creamfrom the cooling chamber.
 17. The method of claim 16, wherein the holdmode is a period of low sales of the frozen ice cream.
 18. The method ofclaim 16, wherein the frozen ice cream is removed through a gate, thegate being opened and closed in coordination with the valve allowingliquid ice cream contents into the cooling chamber.
 19. The method ofclaim 16, further comprising a secondary evaporator about a primaryevaporator about the cooling chamber, wherein the secondary evaporatoris a coiled tube.
 20. The method of claim 16, further comprising asecondary evaporator about a primary evaporator about the coolingchamber, wherein the secondary evaporator surrounds the primaryevaporator.
 21. An ice cream making system, comprising: an evaporatorincluding a cooling chamber, the cooling chamber having an ice creaminput and an ice cream output; a means for restricting access throughthe ice cream input to the cooling chamber; and a means for controllingthe means for restricting so that the cooling chamber is 75 percent orless filled during a hold mode, the hold mode being a state whereadditional ice cream is not being produced.